Method of diagnosing inverter trouble

A method for diagnosing inverter trouble, comprising:

• determining whether each of a plurality of switching devices has a fault by sequentially switching on the switching devices when an inverter is initialized by receiving power;
• recording sorts and fault states of each of the plurality of switching devices having a fault;
• detecting whether an earth fault occurs by outputting each of a plurality of phase voltages of the inverter;
• recording phases having the earth fault and an earth fault state thereof;
• determining inverter trouble based on a fault record of the switching devices and an earth fault record;
• and
• waiting for a normal operation if the inverter has no trouble, and displaying inverter trouble and waiting for an order of a user if inverter trouble occurs, wherein detecting whether an earth fault occurs comprises:
• simultaneously driving a first-phase positive switching device and a second-phase negative switching device so as to detect first-phase current and second-phase current and to compare first-phase current with second-phase current;
• b) simultaneously driving the first-phase positive switching device and a third-phase negative switching device so as to detect first-phase current and third-phase current and to compare first-phase current with third-phase current;
• determining one of the second-phase negative switching device and the third-phase negative switching device as to have the earth fault, if a current value of one of the second-phase negative switching device and the third-phase negative switching device is different from a current value of the first-phase positive switching device;
• and
• d) determining the first-phase positive switching device as to have the earth fault, if current values of the second-phase negative switching device and the third-phase negative switching device are different from the current value of the first-phase positive switching device or if current is not detected.

A method for diagnosing inverter trouble, comprising:

• determining, in response to an inverter receiving power, whether each of a plurality of switching devices has a fault by sequentially switching on the switching devices when an inverter is initialized by receiving power;
• recording whether a fault occurs for each of the plurality of switching devices;
• detecting whether an earth fault occurs by outputting each of a plurality of phase voltages of the inverter;
• recording phases having an earth fault;
• determining inverter trouble based on a fault record of the plurality of switching devices and an earth fault record;
• waiting for a normal operation if the inverter has no trouble;
• and
• displaying inverter trouble and waiting for an order of a user if inverter trouble occurs.